井口头锻件用AISI 4140钢高温热压缩变形行为研究

Flow behavior of AISI 4140 steel for well head forging during hot compression at elevated temperature

利用Gleeble-3500热力模拟试验机,在温度850~1 200℃、应变速率为0.1~10 s^(-1),真应变约为0.9的条件下,研究了井口头锻件用AISI 4140钢的热压缩变形行为.采用双曲正弦模型建立了该材料的高温变形本构方程并绘制了热加工图.结果表明:在热压缩过程中,变形温度升高,峰值应力随之减小;而应变速率增大,峰值应力随之增大.在低应变速率0.1~1 s^(-1)且温度高于1 050℃时,表现出动态再结晶行为特征. AISI 4140钢的热变形激活能为427.469 kJ/mol,最佳热加工温度区间为1 050~1 200℃,应变速率在0.1~1 s^(-1).

The flow stress behavior of AISI 4140 steel for wellhead forging was investigated by hot compression testing on the Gleeble-3500 simulator at the temperature of 850~1 200 ℃,with the strain rate of 0.1~10 s^(-1) and the true strain of 0.9. The high temperature deformation constitutive equation of the material was established by a hyperbolic sinusoidal model and the hot processing maps was drawn. The results shows in the process of hot compression,with the increase of deformation temperature,the peak stress decreases and the strain rate increases. Dynamic recrystallization occurs at low strain rates and temperatures higher than 1 050 ℃. The hot deformation activation energy of AISI 4140 steel is 427.469 kJ/mol,the optimum condition of hot working is that the temperature rang is 1 050~1 200 ℃ and the strain rate is 0.1~1 s^(-1).